It started out as Napster and Scour as the big two but now non Americans seem to be the major players. iMesh is Israeli, WinMX is Canadian,Gnutella has been popular in Europe and heavily developed by Germans. Blubster and Filetopia are Spanish, and many of the OpenNap servers are based in Europe and some in Japan. Many eDonkey servers appear to be European as well. Of course FastTrack is based in the Netherlands.
Just a thought.